Avrom’s Java EE and Oracle ADF Blog

Now that we’ve looked at tuning entity objects and associations, we’ll turn to talking about tuning your ADF view objects for good performance and memory management. There’s a lot to say about tuning view objects (more than for any other business component, in my opinion), so I’m going to break this topic up over two posts. This week, we’ll discover the reasons for and against basing read-only view objects on entity objects, learn how to control how much data is fetched into the middle tier at one time (and how to optimize this for your particular case), and talk about what passivation of view objects is and how to control whether and how much of it happens. Next week, we’ll talk about query-level range paging, forward-only mode, and the spill-to-disk feature for handling very large caches.

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Last week, I talked about tuning your ADF entity objects for maximum performance. This week, I’m going to talk about ADF associations.

Custom Association Views

One of the concepts I covered last week was an entity object’s default query, the all-columns query that would be created in a default view object for that entity object. I also talked about one place where the default query is used, even if you don’t create a default view object: entity object fault-in.

But there’s another place that this possibly inefficient query gets used, at least by default: Whenever your business logic traverses an association accessor.

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This week’s post will be the first of a five-week series about an important but little-discussed topic: Tuning your business components for maximum performance. A lot of projects put very little effort towards business components tuning (usually nothing more than improving the SQL of expert-mode VOs), and because of this, a lot of developers new to the framework come away with the (false) impression that business components perform poorly. Business components actually perform quite well, so long as they’re properly tuned.

This week, I’m going to talk about tuning entity objects. Over the next weeks, I’ll cover associations, view objects, view links, and application modules.

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I’ve posted what is now very nearly an exact copy of my Extreme Reusability series (Part I, Part II) to the ADF Methodology section of the Oracle Wiki here. Why am I putting two separate copies up on the web?

Well, I’m going to use the copy on my blog as a version of Extreme Reusability that I have control over. I’m sure my understanding of the methodology will evolve over time, and I’ll continue to post updates as it does; I also hope that you all will continue to post comments on it here. The version on the Wiki, however, is, more or less, a donated snapshot to the community. All I particularly ask is that people maintain the links I’ve put in it to the two blog posts where I first laid the methodology out. Other than that, the content is fair game for anyone who has ideas, responses, etc.

I’m sick, so no actual substantive post this week–this’ll be it until next Monday.

Hey, did you know that, even if you create a “Programmatic View Object” (rows populated programmatically, not based on a query), you can set “bind variables” for it? Neither did I until very recently. You can’t do it in the Create View Object wizard (because the Query page never appears), but once you’ve got that VO, you can indeed add bind variables in the editor.

“Why on earth would you want to do that?” you ask (or, at least, I imagine you asking). “Bind variables are meant to allow the application or user to specify bind parameters for a query, and a programmatic VO doesn’t have a query.” Indeed, that’s what bind variables are usually for, but here, I’m going to show you, at least in outline, how to use this feature to make the ultimate 100% declaratively customizable framework classes (one view object class, one view definition class) for view object definitions based on REF cursors (i.e., whose instances will call a package function to retrieve their row set, rather than execute a query).

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